Ventilation & Compliance

Question 1

Pulmonary (minute) Ventilation (L/min)

Answer 1

total air movement in/out of lungs

Question 2

Alveolar Ventilation(L/min)

Answer 2

Fresh air getting alveoli and therefore available for gas exchange

Question 3

Air from deadspace

Answer 3

150mL

Question 4

Total Pulmonary Ventilation =

Answer 4

Tidal Volume x Respiratory Rate

Question 5

Tidal Volume

Answer 5

A measure of the amount of air a person inhales during a normal breath

Question 6

Alveolar Ventilation=

Answer 6

Air to alveoli X Respiratory Rate

Question 7

Air to Alveoli =

Answer 7

Tidal - dead space (150)

Question 8

Partial pressure

Answer 8

pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whol gaseous mixture

Question 9

If the atmospheric pressure is 760mmHg (101kPa) and 21% of air we breath is O2 what is the partial pressure of the oxygen we breath

Answer 9

760 X 0.21 = 160mmHg (21kPa)

Question 10

Increased alveolar ventilation

Answer 10

Hyperventilation, PO2 rises and Pco2 falls

Question 11

Decreased alveolar ventilation

Answer 11

Hypoventilation, PO2 falls and PCO2 rises

Question 12

Law of Laplace

Answer 12

Inward directed pressure. The pressure required to keep the alveoli open
P= 2T/r

Question 13

P= 2T/r

Answer 13

T= surface tension
r= radius

Question 14

When does surfactant start to be produced

Answer 14

25 weeks gestation and completes by 36 week

Question 15

Why do babies no need a high change in pressure to inflate lungs

Answer 15

Lungs are filled with fluid and do not need to overcome surface tension (no air-water interface)

Question 16

Compliance

Answer 16

Change in volume relative to change in pressure

Question 17

High Compliance

Answer 17

Large increase in volume for a small decrease in ip pressure- easy for air to enter lungs- steep line

Question 18

Low Compliance

Answer 18

Small increase in lung volume for a large decrease in pressure- difficult to inspire- less steep

Question 19

Emphysema

Answer 19

loss of elastic tissue means expiration requires effort

Question 20

Fibrosis

Answer 20

inert fibrous tissue means effort on inspiration increases

Question 21

Compliance decreases from

Answer 21

base to apex, because of gravity apex is already stretched due to gravity and base is able to expand

Question 22

Small change in intrapleural pressure brings about a larger change in volume at

Answer 22

the base compared to the apex

Question 23

Obstructive

Answer 23

Increased compliance
Increased inspiration
Decreased expiration

Question 24

Restrictive

Answer 24

Loss of lung compliance

Decreased inspiration

Question 25

Examples of Obstructive

Answer 25

Asthma Emphysema Chronic Bronchitis

Question 26

Examples of Restrictive

Answer 26

Fibrosis Infant respiratory distress syndrome (insufficient surfactant) Oedema Pneumothorax

Question 27

Technique used to measure abnormal lung fucntion

Answer 27

Spirometry

Question 28

Spirometry measurements can be

Answer 28

Static: volume exhaled Dynamic: time taken to exhale is being measured as well

Question 29

What volumes can be measured by spirometry

Answer 29

everything except residual volume

Question 30

Functional residual volume

Answer 30

Expiatory reserve volume + residual volume

Question 31

Vital capacity

Answer 31

Expiatory reserve + Inspiratory Capacity + Inspiratory reserve

Question 32

FEV1/FVC ratio is restrictive

Answer 32

High

Question 33

FEV1/FVC in obstructive

Answer 33

low (both FEV1 and FVC fall so air comes out more slowly)

Question 34

FEF (25-75)

Answer 34

Average expired flow over the middle of an FVC

Question 35

Expiratory Reserve Volume

Answer 35

the additional amount of air that can be expired from the lungs by determined effort after normal expiration

Question 36

Functional Residual Capacity

Answer 36

the volume of air present in the lungs at the end of passive expiration

Question 37

Residual Volume

Answer 37

the amount of air that remains in a person's lungs after fully exhaling

Question 38

Vital Capacity

Answer 38

the maximum amount of air a person can expel from the lungs after a maximum inhalation